knee region muscle and movement

Question 1

what movement is your leg in if it is locked

Answer 1

in standard knee extension- the knee joint is locked in closed pack position, joint surfaces more congruent, femoral medial rotation or tibial lateral rotation anf extension tightens ligaments

Question 2

where is the centre of gravity when the knee is locked

Answer 2

COG anterior to knee joint maintaining extension

Question 3

how does the popliteus initiate unlocking mechanisms

Answer 3

by laterally rotating femur on fixed tibia

Question 4

what position are ligamnets and posterior capsule in when the knee is locked

Answer 4

ligaments and posterior capsule are at their most taught- so you can rest in a very energy efficient form with the knee in closed pack position

Question 5

knee locking mechanisms- closed kinetic chain- from sitting to standing

Answer 5

femoral condyles roll anteriorly over tibial condyles, femoral condyles glide posteriorly over tibial condyles (stops femoral condyles rolling off tibial condyles), shorter lateral femoral condyle movements stop first- shorter, femur medially rotates (spins) around fixed lateral condyle to complete the movement

Question 6

knee (un) locking mechanisms

Answer 6

unlocking knee joint into open packed position (flexion)

Question 7

knee (un) locking mechanisms closed pack mechanisms- closed kinetic chain

Answer 7

femur rotates (spins) laterally on the tibia, femoral condyles roll posteriorly on the tibial condyles (relatively fixed), femoral condyles glide anteriorly on the tibial condyles (this stops femoral condyles from rolling off the tibial condyles)

Question 8

Knee extensors rectus femoris- origins and insertions

Answer 8

origins- 2 heads (bipennate)- straight head- AIIS, reflected head- rough area of ilium superior to acetabulum
insertions- 2 heads join quadriceps femoris tendon which inserts into the base of the patella

Question 9

Knee extensors rectus femoris- action and nerve

Answer 9

action 2 joint muscle- extends knee and flexes hip, nerve supply- femoral nerve L2,3,4

Question 10

Knee extensors vastus intermedius- origin and insertions

Answer 10

origin- femur- upper 2/3rds anterior and lateral surfaces, insertions- quadriceps tendon (deep part) and lateral border of patella

Question 11

Knee extensors vastus medialis- origin and insertion

Answer 11

origin- femur-medial part of the intertrochanteric line, pectineal line, medial lip of linea aspera, medial supracondylar line
insertions- quadriceps tendon and medial border of patella- wrap around

Question 12

vastus medialis controversy- historically

Answer 12

VM historically thought to be the only muscle to produce the final 15 degrees of knee extension- therefore patients were given specific exercises to train VM muscle in that range

Question 13

VM controversy- modern evidence

Answer 13

evidence now suggests that VM is not specifically response for the final 15° of knee extension, VM acts throughout the range of knee extension with or without external resistance, VM medalists the patella

Question 14

Knee extensors vastus lateralis- origin and insertion

Answer 14

origin- lateral part of the intertrochanteric line, lateral margin of greater trochanter, lateral margin gluteal tuberosity, lateral lip linea aspera

Question 15

Vastus muscles- action and nerve supply

Answer 15

action- extends the knee, nerve supply- L2,3,4

Question 16

Knee flexion bicep femoris- origin and insertion

Answer 16

origin- 2 heads long head- inferomedial part of upper area ischial tuberosity, short head- lateral lip of linea aspera (lateral supracondylar ridge)
insertion- head of fibula

Question 17

Knee flexion bicep femoris- action and nerve

Answer 17

flexion and ER (lateral), nerve supply- sciatic nerve L5,S2

Question 18

Knee flexion semitendinosus- origin and insertion

Answer 18

origin- inferomedial part of the upper ischial tuberosity

insertion- medial surface proximal tibia

Question 19

Knee flexion semitendinosus- action and nerve

Answer 19

flexion and MR, nerve supply- sciatic nerve L5-S2

Question 20

Knee flexion semimembranosus- origin and insertion

Answer 20

origin- superolateral impression ischial tuberosity

insertion- groove and adjacent bone medial and posterior surface medial tibial condyle

Question 21

Knee flexion semimembranosus- action and nerve

Answer 21

flexion and MR and sciatic nerve L5-S2

Question 22

Hamstring action

Answer 22

all 3 extends the hip and flex at the knee, BF laterally rotates the hip and knee joint, ST and SM medially rotates the hip and knee joints
nerve supply- sciatic nerve L5-S2 (S3 long head)

Question 23

Knee flexion sartorius- origin and insertion

Answer 23

origin- ASIS, insertion- anterior surface of tibia just inferomedial to tibial tuberosity

Question 24

Knee flexion Sartorius- action and nerve

Answer 24

action- MR, flexion (asister), nerve L2,3

Question 25

Knee flexion gracilis- origin and insertion

Answer 25

origin- external surface body of pubis, inferior pubic ramus, ramus of ilium insertion- medial surface of proximal shaft of tibia

Question 26

Knee flexion gracilis- action and nerve

Answer 26

action- assister in medial rotation and flexion at knee | nerve- L3,4

Question 27

Knee flexion gastrocnemius- origin and insertion

Answer 27

origin- 2 heads- medial and lateral heads from medial and lateral femoral condyles insertions- achilles tendon into postero superior calcaneus (heel)

Question 28

Knee flexion gastrocnemius- action and nerve

Answer 28

flex at knee and ankle PF, | Nerve- tibial nerve- S1,2

Question 29

plantaris

Answer 29

NB evolutionary survivor, weak and sometimes not present

Question 30

Knee flexion plantaris- origin and insertion

Answer 30

origin- lateral supracondylar line above lateral head of gastrocnemius insertion- medial border if TA and post surface of calcaneus

Question 31

Knee flexion plantaris- action and nerve

Answer 31

action- weak knee flexor and plantar flexor of foot | nerve- tibial nerve- S1,S2

Question 32

what is the popliteus

Answer 32

small fat, feep, posterior muscle, part of floor of popliteal fossa

Question 33

Knee flexion popliteus- origin and insertion

Answer 33

origin- lateral femoral condyle, insertion- proximal surface of posterior tibia

Question 34

Knee flexion popliteus- action and nerve

Answer 34

action- unlocks the extended knee by laterally rotating the femur on fixed tibia, rotates knee medially, flexes knee nerve supply- tibial nerve L5, S1, S2

Question 35

Knee flexion tensor fasciae latae- origins and insertions

Answer 35

origi- ASIS and outer iliac crest to iliac tubercle | insertion- anterior surface of tibia just inferolateral to tibial tuberosity

Question 36

Knee flexion tensor fasicae latae- action and nerve

Answer 36

stabilises knee laterally, nerve- superior gluteal nerve L5, S1

Question 37

Knee joint active range of motion- flexion and limited by

Answer 37

135°- limited by soft tissue apposition, patellar tendon, PCL

Question 38

Knee joint active range of motion- extension- limited by

Answer 38

0°, = or - 0-5° for hyperextension, limited by posterior capsule, ACL, MCL, LCL, oblique popliteal ligament, tension in antagonists

Question 39

Knee joint active range of motion- medial rotation

Answer 39

20-30° in flexed knee

Question 40

Knee joint active range of motion- lateral rotation

Answer 40

30-40° in flexed knee

Question 41

what limits rotation

Answer 41

both limited by tension in antagonists

Question 42

popliteal fossa borders- laterally

Answer 42

bicep femoris, lateral head of gastrocnemius

Question 43

popliteal fossa borders- medially

Answer 43

semimembranosis, semitendinosus, medial head of gastrocnemius

Question 44

popliteal fossa borders- floor

Answer 44

popliteal surface of femur

Question 45

popliteal fossa borders- roof

Answer 45

Fascia and skin

Question 46

contents of popliteal fossa

Answer 46

popliteal artery and vein, common peroneal and tibial nerve, lymph nodes and fat

Question 47

Knee flexors

Answer 47

bicep femoris, semimembranosis, semitendinosus, gastrocnemius

Question 48

knee extensors

Answer 48

rectus femoris, vastus lateralis, vastus medialis, vastas intermedius

Question 49

medial rotators of tibia on femur

Answer 49

semitendinosus, semimembranosus, sartorius, popliteus

Question 50

lateral rotators of tibia on femur

Answer 50

bicep femoris